String Functions in IIS Url Rewrite Module

The IIS URL Rewrite Module ships with 3 built-in functions:

* ToLower - returns the input string converted to lower case.
* UrlEncode - returns the input string converted to URL-encoded format. This function can be used if the substitution URL in rewrite rule contains special characters (for example non-ASCII or URI-unsafe characters).
* UrlDecode - decodes the URL-encoded input string. This function can be used to decode a condition input before matching it against a pattern.

The functions can be invoked by using the following syntax: {function_name:any_string}

The question is: can this list be extended by introducing a Replace function that's available for changing values within a rewrite rule action or condition?

Another way to frame the question: is there any way to do a global replace on a URL coming in using this module?

It seems that you're limited to using regular expressions and back-references to construct strings - i.e. there's no search/replace mechanism to replace every instance of X with Y in {REQUEST_URI}, wit开发者_运维问答hout knowing how many instances there are.

I've had a quick glance at the extensibility introduced in the 2.0 RTW and don't see any 'light' means of introducing this.

Looks like you have to implement your own provider as shown here:
http://learn.iis.net/page.aspx/804/developing-a-custom-rewrite-provider-for-url-rewrite-module/